8,345 research outputs found

    Synthesis of Thiol Functionalized Multi-walled Carbon Nanotube/Gold Nanoparticle Composites

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    Interdisciplinary School of Green Energyulti-wall carbon nanotubes (MWNTs) were functionalized with 4-mercaptobenzoic acid (4-MBAc) in a polyphosphoric acid (PPA)/phosphorous pentoxide (P2O5). The resultant 4-mercaptobenzoyl-functionalized MWNT (MB-MWNT) was used to immobilize gold nanoparticles (GNPs) via the covalent Au-S bonds. The process involved that GNPs were in-situ synthesized in the presence of MB-MWNT and stabilized by trisodium citrate and sodium borohydride (NaBH4) to covalently deposit onto the surface of MB-MWNTs. The morphology of resultant MB-MWNT/GNP composite showed that GNPs are uniformly distributed on the surface of MB-MWNTs. HR-TEM and XPS studies revealed that GNPs showed well-defined crystal structure. Cyclic voltammetries of MB-MWNT and MB-MWNT/GNP composite showed that MB-MWNT/GNP composite displayed profoundly improved electrocatalytic activity over MB-MWNT.ope

    Carbon-based Electrocatalysts for Oxygen Reduction Reactions

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    Department of Energy EngineeringDue to the rapid industrial development and growing human population, along with the increase in energy demand, the global energy consumption has been accelerating at an alarming rate. At current consumption rate, global energy exhaustion will become inevitable. Fuel cell draws tremendous attention as the upcoming alternative energy source. Because fuel cells are eco-friendly process to produce electricity, water and heat only with no pollutant or toxic by-product, many researches are now focusing on cost down and efficiency up fuel cells. The challenging and current bottleneck lies in the sluggish oxygen reduction reaction (ORR) kinetics on the cathode that significantly limits the efficiency and performance of the fuel cell device. Platinum is the most widely studied noble metal as electrocatalyst. However, it is too expensive and limited reserve in earth. Therefore, exploring new electrocatalysts with enhanced ORR activities and stabilities for the replacement of this costly noble metal with non-platinum alternatives is highly warranted and is of paramount importance to commercialize fuel cells as well as for other renewable energy applications. In this thesis, I explained with a brief overview of ORR in fuel cells and then I introduced my research results, including platinum incorporated multi-walled carbon nanotubes, heteroatom doped graphene and iron encapsulated polymers related with oxygen reduction reaction in both acidic and alkaline medium. Furthermore, these catalysts showed excellent electrocatalytic activities toward ORR with a high selectivity, good tolerance to methanol crossover/CN and SCN poisoning effects, and good long-term cycle stability.ope

    Reducing the Side-Effects of Cisplatin to Improve the Social Acceptance of Chemotherapy as CAM Adjunct in Cancer Treatment

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    Background:In sociology, the prevalence of cancer is interpreted as a broken social contract that requires behaviour change. Complementary and alternative medicine (CAM) is a vital social phenomenon, whose usage is socially patterned out. Perceptions of the limitations of chemotherapy and radiotherapy among cancer patients have contributed to the preference for CAM use, particularly plant-derived polysaccharides like HemoHIM, which contain cisplatin. This research was undertaken to show whether co-administration of vitamin C with cisplatin in chemotherapy can prevent or reduce the side-effects of cisplatin nephrotoxicity. Objectives:The objective of this study was to overturn social perceptions of conventional therapy as associated with nephrotoxicity. It investigates the renoprotective effects of high-dose vitamin C by performing an animal experiment to determine body weight, organ weight, and biochemical blood parameters; as well as to measure inflammatory cytokines. Design:Mice were randomly divided into five groups (control; and 500, 1000, and 2000 mg/kg of vitamin C with cisplatin). All groups except for the control group were intraperitoneally injected with 5- mg/kg cisplatin for 10 days, and the mice in the respective groups were orally administered each 500-, 1000-, 2000- mg/kg vitamin C 2 h prior to cisplatin treatment. After 10 days, the mice were sacrificed, and their blood samples and kidney tissues were obtainedfor further analysis. Setting and location:Republic of Korea Methods:Blood samples from animal experiments and tissue preparation were analyzed using real-time quantitative polymerase chain reaction. Results:The intraperitoneal injection of cisplatinreduced body weight, and elevated levels of blood urea nitrogen, serum creatinine, and uric acid. It also triggered an inflammatory response in the mouse kidney by inducing the pro-inflammatory cytokines TNFα, IL-6, and IL-1β and increasing in the expression of iNOS, and IL-4. Renal injury was decreased by the administration of vitamin C; the oral administration of vitamin C (500, 1000, 2000 mg/kg) decreased or normalized the renal function through the attenuation of cisplatin-induced inflammatory cytokines and the modulation of biochemical parameters (ALT, AST, cholesterol, TG, HDL, LDL, blood urea nitrogen, creatinine, and Uric acid) following the intraperitoneal injection of cisplatin. Conclusion:The results of our present study suggest that the co-administration of vitamin C with cisplatin chemotherapy is a promising method to prevent or reduce the side effects of cisplatin nephrotoxicity. These findings can remodel how the Korean society thinks, approaches and fights cancer by showing how nephrotoxicity can be counteracted to ensure social acceptance of CAM as an adjunctive to cisplatin therapy. Keywords:Complementary and alternative medicine, CAM, Vitamin C, Renoprotective therapy, Cisplatin, Nephrotoxicity, High-dose vitamin C DOI: 10.7176/JHMN/81-11 Publication date:October 31st 2020

    Stability of hydrogenation states of graphene and conditions for hydrogen spillover

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    The hydrogen spillover mechanism has been discussed in the field of hydrogen storage and is believed to have particular advantage over the storage as metal or chemical hydrides. We investigate conditions for practicality realizing the hydrogen spillover mechanism onto carbon surfaces, using first-principles methods. Our results show that contrary to common belief, types of hydrogenation configurations of graphene (the aggregated all-paired configurations) can satisfy the thermodynamic requirement for room-temperature hydrogen storage. However, the peculiarity of the paired adsorption modes gives rise to a large kinetic barrier against hydrogen migration and desorption. It means that an extremely high pressure is required to induce the migration-derived hydrogenation. However, if mobile catalytic particles are present inside the graphitic interstitials, hydrogen migration channels can open and the spillover phenomena can be realized. We suggest a molecular model for such a mobile catalyst which can exchange hydrogen atoms with the wall of graphene.open151


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    Pengaruh globalisasi mendatangkan sebuah fenomena yaitu Masyarakat Ekonomi ASEAN (MEA) atau ASEAN Economic Community (AEC). Globalisasi memberikan pengaruh yang besar dalam dunia industri dan organisasi yaitu menghubungkan kegiatan industri dan organisasi menjadi tanpa batas. Pada perusahan yang akan penulis teliti yakni PT. Bintang Family berlokasi di Indonesia Bandung belum mampu menstabilkan pendapatan penjualan pokok Fenomena tersebut mengindikasikan masih rendahnya kinerja pegawai. Tinggi rendahnya kinerja pegawai tersebut diprediksi oleh tinggi rendahnya variabel – variabel yang mempengaruhinya, yaitu kepemimpinan lintas budaya ekspatriat dan kepuasan kerja. Penelitian ini menggunakan survey dengan jenis verificative explanation reseach terhadap 63 pegawai. Analisis dan interpretasi hasil pengolahan data menggunakan analisis deskriptif dan analisis verifikatif (Partial Least Square). Hasil analisis menunjukan bahwa variabel kepemimpinan lintas budaya ekspatriat Korea Selatan termasuk kedalam kategori tinggi sedangkan variabel kepuasan kerja serta kinerja termasuk kategori cukup serta kuat lemahnya kepemimpinan lintas budaya Korea Selatan memiliki pengaruh yang positif dan signifikan terhadap tinggi rendahnya kepuasan kerja dan kinerja karyawan. Tinggi rendahnya kepuasan kerja memiliki pengaruh positif dan signifikan terhadap tinggi rendahnya kinerja karyawan.;--The influence of globalization brings a phenomenon of the ASEAN Economic Community (MEA) or ASEAN Economic Community (AEC). Globalization has a great influence in the industrial and organizational world of connecting industrial and organizational activities with no limits. At the company to be the author thoroughly ie PT. Bintang Family located in Indonesia Bandung has not been able to stabilize the sales revenue of the principal The phenomenon indicates the low performance of employees. The high level of employee performance is predicted by the high and low variables that influence it, namely the cross-cultural leadership of expatriates and job satisfaction. This research uses survey with verificative explanation reseach type to 63 employees. Analysis and interpretation of data processing using descriptive analysis and verifikatif analysis (Partial Least Square). The results of the analysis showed that cross-cultural expatriate leadership variables of South Korea are included in the high category while job satisfaction and performance variables including strong category and strong weakness of cross-cultural leadership of South Korea have a positive and significant influence on the high and low job satisfaction and employee performance. The high level of job satisfaction has a positive and significant impact on the high and low employee performance

    A Three-Decade Decline in the Homeownership Gender Gap: What Drove the Change, and Where Do We Go from Here?

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    Over the past 30 years, women have made tremendous gains in closing both the income and the education gaps between them and men, and growth in their homeownership rates has become an important manifestation of these trends. In 1990, there were 15.7 million female-headed homeowner households. By 2019, that number had reached 39.2 million. In contrast, the number of male-headed homeowner households decreased from 44.4 million to 43.1 million.In this report, we examine homeownership by the gender of the household head and how it has changed over the past three decades. Our analysis explores factors narrowing the homeownership gender gap, overall and by race and ethnicity. This narrowing can be attributed mostly to gains in household income, followed closely by the fact that more married women are head of household

    On SS-nn-absorbing ideals

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    Let RR be a commutative ring with identity, SS a multiplicative subset of RR and II an ideal of RR disjoint from SS. In this paper, we introduce the notion of an SS-nn-absorbing ideal which is a generalization of both the SS-prime ideals and nn-absorbing ideals. Moreover, we investigate the basic properties, quotient extension, existence and amalgamation of SS-nn-absorbing ideals.Comment: 18page